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model. An improperly ventilated equipment room can
get excessively hot and cause accelerated deterioration
of controls and electrical components.
Pool heaters installed in vaults (“pits”) must have
combustion air ducted to bottom of the vault, even if
the top is unobstructed. Ducting should be sized for
a minimum of one square inch (6.5 sq. cm) per 2,000
BTU/hr input of the total input rating of all appliances
in the vault. Contact the Service Department for more
information.
In Canada, Table 2 does not apply. Consult local
building codes or, in the absence of such requirements,
follow CSA B149.1 standard.
b. Forced-Air Ventilation
In the United States: any equipment which
exhausts air from the heater room can deplete the
combustion air supply or reverse the natural draft
action of the venting system. This could cause flue
products to accumulate in the heater room. Additional
air must be supplied to compensate for such exhaust.
The information in Table 2 is not applicable in
installations where exhaust fans or blowers of any
type are used. Such installations must be designed by
qualified engineers.
In Canada: follow Canadian standard, CSA
B149.1 or local codes.
If a blower or fan is used to supply air to the
heater room, the installer should make sure it does not
create drafts which could cause nuisance shutdowns of
the pilot. If a blower is necessary to provide adequate
combustion air to the heater, a suitable switch or
interlock must be wired into the heater control circuit
to prevent the heater from firing unless the blower is
operating.
The heater must be completely isolated and
protected from any source of corrosive chemical fumes
such as trichlorethylene, perchloroethylene, chlorine, etc.
2.2.2 Venting
These pool heaters have built-in draft diverters
for natural draft operation and must not be connected
to any portion of a mechanical draft system under
positive pressure. The flue outlet must be connected
to a clear, unobstructed vent of adequate capacity
ending above the highest point of the building with
an approved vent cap. The venting system should
be installed according to the latest edition of ANSI
Z223.1 and/or, in Canada, CSA B149.1 and any local
codes having jurisdiction.
Do not weld or fasten the vent pipe to the heater
drafthood. The weight of the stack must not rest on the
heater. The drafthood and heater top must be easily
removable for normal heater service and inspection.
IMPORTANT NOTE:
Do not use sheet metal
screws at the snap lock joints of Type B gas vents.
Figure 6. Alcove Installation.
* When the ceiling height exceeds 8 feet, you are only allowed to consider 8
feet when calculating the total volume of the enclosure.
Water
Heater
CLOSET INSTALLATION
(UNACCEPTABLE)
A closet is any 4 sided enclosure
which is less than 16* times the total
volume of all the gas fired appliances
within the enclosure.
ROOM INSTALLATION
(ACCEPTABLE)
A room is any enclosure which is at
least 16* times greater than the total
volume of all the gas fired appliances
within the enclosure.
Water
Heater
ALCOVE INSTALLATION
(ACCEPTABLE)
An alcove suitable for the installation
of a water heater is a restricted sec
-
tion of a room not separated from
the room by a door or partition and
which meets the minimum clearances
for the specific model water heater
listed below.
Figure 4 - Typical Heater Installation on Roof
Using 4x4 Stringer
Figure 5 - Installation on Concrete Blocks or Tile
Base must extend out
min. 12" (305mm) on
all sides of
heater frame.
20 ga. min.
galvanized sheet
metal
under entire
heater.
Concrete blocks or tile min. 7" (178mm)
high with 3" (76mm) min. air openings.
Blocks must provide solid base and be braced so they
cannot slip out of place. Air openings in blocks must be
arranged to provide unobstructed opening through entire
width or length of base.
MightyTherm Pool Heater
